Answer:5. Underline if or unless.
1. If you drive more carefully, you will have an accident.
2. The old lady'll get lost unless someone shows her the way.
3. If you practice your Russian, you can improve it quickly.
4. If you don't hurry, you'll be late for school again.
5. If you go to bed late, you'll feel tired in the morning.
6. If I study, I will pass the exam.
7. If you don't keep your promises, you'll lose your friends.
8. You can't travel abroad if you don't have a passport.
Step-by-step explanation: